Novel guanosine triphosphate (GTP) binding protein-coupled receptor protein, BG3

Abstract

The present inventors isolated a cDNA which encodes a novel human G protein-coupled receptor protein, by deducing a unique region highly conserved among known G protein-coupled receptor proteins and screening cDNAs by using the probe corresponding to the region. The G protein-coupled receptor protein of the present invention can be used to screen for ligands and candidate pharmaceutical compounds capable of modulating the signal transduction mediated by the receptor.

What is claimed:  
     
         1 . A substantially pure polypeptide comprising an amino acid sequence at least 70% identical to SEQ ID NO:6, wherein the polypeptide has a G protein-coupled receptor protein activity.  
     
     
         2 . The polypeptide of  claim 1 , wherein the amino acid sequence is at least 80% identical to SEQ ID NO:6.  
     
     
         3 . The polypeptide of  claim 1 , wherein the amino acid sequence is at least 90% identical to SEQ ID NO:6.  
     
     
         4 . A substantially pure polypeptide, the sequence of which consists of SEQ ID NO:6.  
     
     
         5 . A substantially pure polypeptide, the sequence of which consists of SEQ ID NO:6 with up to 30 conservative amino acid substitutions, deletions or insertions, wherein the polypeptide has a G protein-coupled receptor protein activity.  
     
     
         6 . A substantially pure polypeptide comprising the sequence of SEQ ID NO:6, or a fragment thereof that (a) has a G-protein receptor coupled protein activity or (b) is immunogenic.  
     
     
         7 . A substantially pure polypeptide encoded by a nucleic acid that hybridizes under high stringency conditions to the sequence of SEQ ID NO:5, wherein the polypeptide has a G protein-coupled receptor protein activity.  
     
     
         8 . An isolated nucleic acid encoding the polypeptide of  claim 1 .  
     
     
         9 . An isolated nucleic acid encoding t he polypeptide of  claim 4 .  
     
     
         10 . An isolated nucleic acid encoding the polypeptide of  claim 5 .  
     
     
         11 . An isolated nucleic acid comprising a strand that hybridizes under high stringency conditions to the sequence of SEQ ID NO:5, or the complement of SEQ ID NO:5.  
     
     
         12 . The isolated nucleic acid of  claim 11 , wherein the nucleic acid encodes a polypeptide having a G protein-coupled receptor protein activity.  
     
     
         13 . The nucleic acid of  claim 11 , wherein the strand is at least 15 nucleotides in length.  
     
     
         14 . An isolated nucleic acid comprising the sequence of SEQ ID NO:5.  
     
     
         15 . An isolated nucleic acid comprising a sequence encoding the polypeptide of SEQ ID NO:6.  
     
     
         16 . An antibody that specifically binds to the polypeptide consisting of SEQ ID NO:6.  
     
     
         17 . A vector comprising the nucleic acid of  claim 8 .  
     
     
         18 . A vector comprising the nucleic acid of  claim 11 .  
     
     
         19 . A vector comprising the nucleic acid of  claim 14 .  
     
     
         20 . A vector comprising the nucleic acid of  claim 15 .  
     
     
         21 . A cultured host cell comprising the nucleic acid of  claim 8 .  
     
     
         22 . A cultured host cell comprising the nucleic acid of  claim 11 .  
     
     
         23 . A cultured host cell comprising the nucleic acid of  claim 14 .  
     
     
         24 . A cultured host cell comprising the nucleic acid of  claim 15 .  
     
     
         25 . An antibody that specifically binds to the polypeptide of  claim 1 .  
     
     
         26 . A method of producing a polypeptide, the method comprising culturing the cultured host cell of  claim 21  under conditions that permit expression of the polypeptide in the cell.  
     
     
         27 . A method for identifying a compound that modulates a G protein-coupled receptor activity, comprising the steps of: 
 a) contacting a polypeptide of  claim 1 , or a cell transfected with a nucleic acid encoding the polypeptide of  claim 1 , with a test compound; and    b) determining whether the test compound modulates a G protein-coupled receptor activity of the polypeptide or cell, thereby identifying a compound that modulates a G protein-coupled receptor activity.    
     
     
         28 . A kit comprising the polypeptide of  claim 1  and instructions for use in a method of screening.  
     
     
         29 . A compound isolated by the method of  claim 27 .  
     
     
         30 . A pharmaceutical composition comprising the compound of  claim 29  as an active ingredient.